• 한국광학회지
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• 제14권2호
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• pp.166-168
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• 2003

반도체 광증폭기의 이득포화원리를 이용한 전광 AND논리소자가 10 Gb/s에서 처음으로 구현되었다. 먼저 첫 번째 반도체 광증폭기에 B 신호를 입력시켜 반전된 신호인 Boolean (equation omitted)이 얻어졌다. 이와 같이 반전된 신호는 두 번째 반도체 광증폭기에 A신호와 함께 동시 입력되어 AND논리소자의 특성이 얻어졌다.

• Current Optics and Photonics
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• 제1권6호
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• pp.579-586
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• 2017

In this paper, we theoretically demonstrate that semiconductor optical amplifiers (SOAs) with strong wavelength dependence of gain and phase are capable of all-optical inverted and non-inverted wavelength conversion (WC) over a wide range, with the assistance of an optical filter. First, the gain dynamics and phase dynamics in a common quantum well (QW) SOA with the $In_{0.53}Ga_{0.47}As/In_{0.7322}Ga_{0.2678}As_{0.5810}P_{0.4190}$ material system are found to be strongly dependent on wavelength, which is mainly related to the wavelength dependence of the differential gain and the differential refractive-index change. Second, the wavelength dependence in an all-optical wavelength converter based on the QW SOA cascaded with a detuning band pass filter is studied. Simulations show that the quality of the converted signal has little dependence on the operation wavelength. Both inverted and non-inverted WC can be achieved, over a large wavelength range. Therefore, although the gain and phase change are strongly wavelength-dependent, the effects of this dependence can be erased by appropriate optical filtering.

• ETRI Journal
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• 제28권1호
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• pp.1-8
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• 2006

A novel all-optical gain-controlled (AOGC) bidirectional amplifier is proposed and demonstrated in a compact structure. The AOGC function using fiber Bragg grating (FBG) pairs controls both directional signals independently, and combinations of optical interleavers and isolators suppress Rayleigh backscattering (RB) noise. The amplifier achieves high and constant gain with a wide dynamic input signal range and low noise figure. The performance does not depend on the input signal conditions, whether static-state or transient signals, or whether there is symmetric or asymmetric data traffic on bidirectional transmission. Transmission comparison experiments between invariable symmetrical and random variable asymmetric bidirectional data traffic verify that the all-optical gain control and bidirectional amplification functions are successfully combined into this proposed amplifier.

• 한국광학회지
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• 제17권6호
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• pp.564-568
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• 2006

반도체 광증폭기에 기반을 둔 이득포화특성을 이용하여 XOR, AND, OR 논리 게이트를 동시에 구현하는 다기능 전광 논리소자를 설계하고 구현하였다. 상용화된 프로그램인 VPI Component $Maker^{TM}$을 사용하여 시뮬레이션을 수행하였고 10 Gbit/s의 입력 신호를 사용하여 XOR, AND, OR 논리동작을 동시에 구현하는 다기능 전광 논리소자를 구현하였다.

• Current Optics and Photonics
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• 제4권6호
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• pp.472-476
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• 2020

We have investigated the impact of optical filter bandwidth on the performance of all-optical automatic gain-controlled (AGC) erbium-doped fiber amplifiers (EDFAs). In principle, an optical bandpass filter (OBPF) should be placed within the feedback gain-clamping loop to set the lasing wavelength as well as the passband of the feedback amplified spontaneous emission (ASE) in all-optical AGC EDFA. From our measurement results, we found that the power level of feedback ASE with 0.1 nm passband of the optical filter was smaller than the ones with >0.2 nm passband cases. Therefore, the peak-to-peak power variation of the surviving channel with 0.1 nm passband was much larger than the ones with >0.2 nm passband. In addition, no significant difference in the power level of the feedback ASE was observed when the passband of the optical filter was ranging from 0.2 nm to 4.5 nm in our measurements. From these results, we have concluded that the passband of the optical filter should be slightly larger than 0.2 nm by taking into account the effect of feedback ASE power and the efficient use of the EDFA gain spectrum for the lasing ASE peak.

• ETRI Journal
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• 제29권5호
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• pp.633-640
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• 2007

We report an experimental demonstration of 40 Gbps all-optical 3R regeneration with all-optical clock recovery based on InP semiconductor devices. We also obtain alloptical non-return-to-zero to return-to-zero (NRZ-to-RZ) format conversion using the recovered clock signal at 10 Gbps and 40 Gbps. It leads to a good performance using a Mach-Zehnder interferometric wavelength converter and a self-pulsating laser diode (LD). The self-pulsating LD serves a recovered clock, which has an rms timing jitter as low as sub-picosecond. In the case of 3R regeneration of RZ data, we achieve a 1.0 dB power penalty at $10^{-9}$ BER after demultiplexing 40 Gbps to 10 Gbps with an eletroabsorption modulator. The regenerated 3R data shows stable error-free operation with no BER floor for all channels. The combination of these functional devices provides all-optical 3R regeneration with NRZ-to-RZ conversion.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.12-13
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• 2002

The performance improvement of 40Gbit/s soliton transmission system employing nonlinear optical loop mirror (NOLM) as all-optical regenerative repeater is investigated. The switching characteristic of NOLM is optimized using our design strategies. By inserting the optical repeater where the eye-penalty of the transmitted signal becomes 1 ㏈, we achieve the improvement of 0.3㏈ eye-penalty resulting in further 480km transmission distance.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.119-122
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• 1989

An intermodal switch based on optically-induced (through optical Kerr effect) periodic coupling in a two-mode waveguide is described and demonstrated. A high power pump beam injected into the two modes of the waveguide produced a periodic modulation of the refractive index profile with a period of modal beat length. this causes an intermodal coupling of the prove beam. The operating principle was successfully demonstrated in an elliptical core two-mode fiber with a counter-propagating pump-probe scheme.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1109-1112
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• 2002

A non-coherent synchronous all-optical code-division multiple-access (CDMA) network is proposed. In this network, symmetric codes derived from prime sequence codes are used. We present the construction of symmetric codes and show that the pseudo-orthogonality of the new codes is the same as that of the original prime-sequence codes while the cardinality of the new codes is larger than that of the prime sequence codes and the modified prime codes in the same field GF(p). Therefore, an optical CDMA LAN using symmetric codes can have a larger number of potential subscribers. The new codes allow designing fully programmable serial all-optical transmitter and receiver suitable for low-loss, high-capacity, optical CDMA LANs. It is also shown that compared to systems using modified prime codes the proposed system can achieve better BER performance for low received chip optical power.

• Current Optics and Photonics
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• 제4권5호
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• pp.405-410
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• 2020

A new all-optical flip-flop (AOFF) method based on the absorption nulls of an injection-locked Fabry-Perot laser diode (FP-LD) in transverse magnetic (TM) mode is proposed and experimentally demonstrated. For the set and reset operations of the AOFF, injection locking and the destructive minus of beating in transverse electric (TE) mode are used. The absorption nulls on the TM mode are modulated according to the operations, and then non-inverted (Q) and inverted (${\bar{Q}}$) outputs can be obtained simultaneously. Thanks to the use of several absorption nulls, the proposed AOFF can achieve multiple outputs with extinction ratios of more than 15 dB. Even though the experiment is demonstrated at 100 Mbit/s, the results of previous experiments using the injection of a CW holding beam imply that the operation speed can increase to 10 Gbit/s.